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Shashkova S, Nyström T, Leake MC. Copy Number Analysis of the Yeast Histone Deacetylase Complex Component Cti6 Directly in Living Cells. Methods Mol Biol 2022; 2476:183-190. [PMID: 35635705 DOI: 10.1007/978-1-0716-2221-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Proteins are one of the key components of cellular life that play a crucial role in most biological processes. Therefore, quantification of protein copy numbers is essential for revealing and better understanding of cellular behavior and functions. Here we describe a single-molecule fluorescence-based method of protein copy number quantification directly in living cells. This enables quick and reliable estimations and comparison of the protein of interest abundance without implementing large-scale studies.
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Affiliation(s)
- Sviatlana Shashkova
- Department of Microbiology and Immunology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
- Departments of Physics and Biology, University of York, York, UK.
| | - Thomas Nyström
- Department of Microbiology and Immunology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mark C Leake
- Departments of Physics and Biology, University of York, York, UK
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Lecinski S, Shepherd JW, Frame L, Hayton I, MacDonald C, Leake MC. Investigating molecular crowding during cell division and hyperosmotic stress in budding yeast with FRET. CURRENT TOPICS IN MEMBRANES 2021; 88:75-118. [PMID: 34862033 PMCID: PMC7612257 DOI: 10.1016/bs.ctm.2021.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cell division, aging, and stress recovery triggers spatial reorganization of cellular components in the cytoplasm, including membrane bound organelles, with molecular changes in their compositions and structures. However, it is not clear how these events are coordinated and how they integrate with regulation of molecular crowding. We use the budding yeast Saccharomyces cerevisiae as a model system to study these questions using recent progress in optical fluorescence microscopy and crowding sensing probe technology. We used a Förster Resonance Energy Transfer (FRET) based sensor, illuminated by confocal microscopy for high throughput analyses and Slimfield microscopy for single-molecule resolution, to quantify molecular crowding. We determine crowding in response to cellular growth of both mother and daughter cells, in addition to osmotic stress, and reveal hot spots of crowding across the bud neck in the burgeoning daughter cell. This crowding might be rationalized by the packing of inherited material, like the vacuole, from mother cells. We discuss recent advances in understanding the role of crowding in cellular regulation and key current challenges and conclude by presenting our recent advances in optimizing FRET-based measurements of crowding while simultaneously imaging a third color, which can be used as a marker that labels organelle membranes. Our approaches can be combined with synchronized cell populations to increase experimental throughput and correlate molecular crowding information with different stages in the cell cycle.
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Affiliation(s)
- Sarah Lecinski
- Department of Physics, University of York, York, United Kingdom
| | - Jack W Shepherd
- Department of Physics, University of York, York, United Kingdom; Department of Biology, University of York, York, United Kingdom
| | - Lewis Frame
- School of Natural Sciences, University of York, York, United Kingdom
| | - Imogen Hayton
- Department of Biology, University of York, York, United Kingdom
| | - Chris MacDonald
- Department of Biology, University of York, York, United Kingdom
| | - Mark C Leake
- Department of Physics, University of York, York, United Kingdom; Department of Biology, University of York, York, United Kingdom.
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Shashkova S, Nyström T, Leake MC, Wollman AJM. Correlative single-molecule fluorescence barcoding of gene regulation in Saccharomyces cerevisiae. Methods 2020; 193:62-67. [PMID: 33086048 PMCID: PMC8343463 DOI: 10.1016/j.ymeth.2020.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/07/2020] [Accepted: 10/15/2020] [Indexed: 01/14/2023] Open
Abstract
Most cells adapt to their environment by switching combinations of genes on and off through a complex interplay of transcription factor proteins (TFs). The mechanisms by which TFs respond to signals, move into the nucleus and find specific binding sites in target genes is still largely unknown. Single-molecule fluorescence microscopes, which can image single TFs in live cells, have begun to elucidate the problem. Here, we show that different environmental signals, in this case carbon sources, yield a unique single-molecule fluorescence pattern of foci of a key metabolic regulating transcription factor, Mig1, in the nucleus of the budding yeast, Saccharomyces cerevisiae. This pattern serves as a 'barcode' of the gene regulatory state of the cells which can be correlated with cell growth characteristics and other biological function.
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Affiliation(s)
- Sviatlana Shashkova
- Department of Microbiology and Immunology, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden.
| | - Thomas Nyström
- Department of Microbiology and Immunology, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden.
| | - Mark C Leake
- Department of Physics, University of York, YO10 5DD York, United Kingdom.
| | - Adam J M Wollman
- Newcastle University Biosciences Institute, Newcastle NE2 4HH, United Kingdom.
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Wollman AJ, Muchová K, Chromiková Z, Wilkinson AJ, Barák I, Leake MC. Single-molecule optical microscopy of protein dynamics and computational analysis of images to determine cell structure development in differentiating Bacillus subtilis. Comput Struct Biotechnol J 2020; 18:1474-1486. [PMID: 32637045 PMCID: PMC7327415 DOI: 10.1016/j.csbj.2020.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
Here we use singe-molecule optical proteomics and computational analysis of live cell bacterial images, using millisecond super-resolved tracking and quantification of fluorescently labelled protein SpoIIE in single live Bacillus subtilis bacteria to understand its crucial role in cell development. Asymmetric cell division during sporulation in Bacillus subtilis presents a model system for studying cell development. SpoIIE is a key integral membrane protein phosphatase that couples morphological development to differential gene expression. However, the basic mechanisms behind its operation remain unclear due to limitations of traditional tools and technologies. We instead used advanced single-molecule imaging of fluorescently tagged SpoIIE in real time on living cells to reveal vital changes to the patterns of expression, localization, mobility and stoichiometry as cells undergo asymmetric cell division then engulfment of the smaller forespore by the larger mother cell. We find, unexpectedly, that SpoIIE forms tetramers capable of cell- and stage-dependent clustering, its copy number rising to ~ 700 molecules as sporulation progresses. We observed that slow moving SpoIIE clusters initially located at septa are released as mobile clusters at the forespore pole as phosphatase activity is manifested and compartment-specific RNA polymerase sigma factor, σF, becomes active. Our findings reveal that information captured in its quaternary organization enables one protein to perform multiple functions, extending an important paradigm for regulatory proteins in cells. Our findings more generally demonstrate the utility of rapid live cell single-molecule optical proteomics for enabling mechanistic insight into the complex processes of cell development during the cell cycle.
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Affiliation(s)
- Adam J.M. Wollman
- Departments of Physics and Biology, University of York, York YO10 5DD, United Kingdom
| | - Katarína Muchová
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Zuzana Chromiková
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Anthony J. Wilkinson
- Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Imrich Barák
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Mark C. Leake
- Departments of Physics and Biology, University of York, York YO10 5DD, United Kingdom
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Miller HL, Contera S, Wollman AJM, Hirst A, Dunn KE, Schröter S, O'Connell D, Leake MC. Biophysical characterisation of DNA origami nanostructures reveals inaccessibility to intercalation binding sites. NANOTECHNOLOGY 2020; 31:235605. [PMID: 32125281 DOI: 10.1088/1361-6528/ab7a2b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Intercalation of drug molecules into synthetic DNA nanostructures formed through self-assembled origami has been postulated as a valuable future method for targeted drug delivery. This is due to the excellent biocompatibility of synthetic DNA nanostructures, and high potential for flexible programmability including facile drug release into or near to target cells. Such favourable properties may enable high initial loading and efficient release for a predictable number of drug molecules per nanostructure carrier, important for efficient delivery of safe and effective drug doses to minimise non-specific release away from target cells. However, basic questions remain as to how intercalation-mediated loading depends on the DNA carrier structure. Here we use the interaction of dyes YOYO-1 and acridine orange with a tightly-packed 2D DNA origami tile as a simple model system to investigate intercalation-mediated loading. We employed multiple biophysical techniques including single-molecule fluorescence microscopy, atomic force microscopy, gel electrophoresis and controllable damage using low temperature plasma on synthetic DNA origami samples. Our results indicate that not all potential DNA binding sites are accessible for dye intercalation, which has implications for future DNA nanostructures designed for targeted drug delivery.
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Affiliation(s)
- Helen L Miller
- Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom
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Wollman AJM, Hedlund EG, Shashkova S, Leake MC. Towards mapping the 3D genome through high speed single-molecule tracking of functional transcription factors in single living cells. Methods 2019; 170:82-89. [PMID: 31252059 PMCID: PMC6971689 DOI: 10.1016/j.ymeth.2019.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/22/2019] [Indexed: 10/26/2022] Open
Abstract
How genomic DNA is organized in the nucleus is a long-standing question. We describe a single-molecule bioimaging method utilizing super-localization precision coupled to fully quantitative image analysis tools, towards determining snapshots of parts of the 3D genome architecture of model eukaryote budding yeast Saccharomyces cerevisiae with exceptional millisecond time resolution. We employ astigmatism imaging to enable robust extraction of 3D position data on genomically encoded fluorescent protein reporters that bind to DNA. Our relatively straightforward method enables snippets of 3D architectures of likely single genome conformations to be resolved captured via DNA-sequence specific binding proteins in single functional living cells.
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Affiliation(s)
- Adam J M Wollman
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Erik G Hedlund
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Sviatlana Shashkova
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
| | - Mark C Leake
- Biological Physical Science Institute, Departments of Physics and Biology, University of York, YO10 5DD York, UK.
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Shashkova S, Wollman AJM, Leake MC, Hohmann S. The yeast Mig1 transcriptional repressor is dephosphorylated by glucose-dependent and -independent mechanisms. FEMS Microbiol Lett 2018; 364:3884263. [PMID: 28854669 DOI: 10.1093/femsle/fnx133] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 06/21/2017] [Indexed: 12/28/2022] Open
Abstract
A yeast Saccharomyces cerevisiae Snf1 kinase, an analog of mammalian AMPK, regulates glucose derepression of genes required for utilization of alternative carbon sources through the transcriptional repressor Mig1. It has been suggested that the Glc7-Reg1 phosphatase dephosphorylates Mig1. Here we report that Mig1 is dephosphorylated by Glc7-Reg1 in an apparently glucose-dependent mechanism but also by a mechanism independent of glucose and Glc7-Reg1. In addition to serine/threonine phosphatases another process including tyrosine phosphorylation seems crucial for Mig1 regulation. Taken together, Mig1 dephosphorylation appears to be controlled in a complex manner, in line with the importance for rapid and sensitive regulation upon altered glucose concentrations in the growth medium.
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Affiliation(s)
- Sviatlana Shashkova
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530 Göteborg, Sweden.,Biological Physical Sciences Institute, University of York, York YO10 5DD, UK
| | - Adam J M Wollman
- Biological Physical Sciences Institute, University of York, York YO10 5DD, UK
| | - Mark C Leake
- Biological Physical Sciences Institute, University of York, York YO10 5DD, UK
| | - Stefan Hohmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, 40530 Göteborg, Sweden.,Department of Biology and Biological Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden
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Shashkova S, Leake MC. Single-molecule fluorescence microscopy review: shedding new light on old problems. Biosci Rep 2017; 37:BSR20170031. [PMID: 28694303 PMCID: PMC5520217 DOI: 10.1042/bsr20170031] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 12/19/2022] Open
Abstract
Fluorescence microscopy is an invaluable tool in the biosciences, a genuine workhorse technique offering exceptional contrast in conjunction with high specificity of labelling with relatively minimal perturbation to biological samples compared with many competing biophysical techniques. Improvements in detector and dye technologies coupled to advances in image analysis methods have fuelled recent development towards single-molecule fluorescence microscopy, which can utilize light microscopy tools to enable the faithful detection and analysis of single fluorescent molecules used as reporter tags in biological samples. For example, the discovery of GFP, initiating the so-called 'green revolution', has pushed experimental tools in the biosciences to a completely new level of functional imaging of living samples, culminating in single fluorescent protein molecule detection. Today, fluorescence microscopy is an indispensable tool in single-molecule investigations, providing a high signal-to-noise ratio for visualization while still retaining the key features in the physiological context of native biological systems. In this review, we discuss some of the recent discoveries in the life sciences which have been enabled using single-molecule fluorescence microscopy, paying particular attention to the so-called 'super-resolution' fluorescence microscopy techniques in live cells, which are at the cutting-edge of these methods. In particular, how these tools can reveal new insights into long-standing puzzles in biology: old problems, which have been impossible to tackle using other more traditional tools until the emergence of new single-molecule fluorescence microscopy techniques.
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Affiliation(s)
- Sviatlana Shashkova
- Department of Physics, Biological Physical Sciences Institute (BPSI), University of York, York YO10 5DD, U.K
- Department of Biology, Biological Physical Sciences Institute (BPSI), University of York, York YO10 5DD, U.K
| | - Mark C Leake
- Department of Physics, Biological Physical Sciences Institute (BPSI), University of York, York YO10 5DD, U.K.
- Department of Biology, Biological Physical Sciences Institute (BPSI), University of York, York YO10 5DD, U.K
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Wollman AJM, Miller H, Foster S, Leake MC. An automated image analysis framework for segmentation and division plane detection of single liveStaphylococcus aureuscells which can operate at millisecond sampling time scales using bespoke Slimfield microscopy. Phys Biol 2016; 13:055002. [DOI: 10.1088/1478-3975/13/5/055002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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